diff options
Diffstat (limited to 'src/libsyntax/parse')
| -rw-r--r-- | src/libsyntax/parse/parser.rs | 215 |
1 files changed, 134 insertions, 81 deletions
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index 5f097256318..f76de1f04ce 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -17,8 +17,8 @@ use ast::{Public, Unsafety}; use ast::{Mod, BiAdd, Arg, Arm, Attribute, BindByRef, BindByValue}; use ast::{BiBitAnd, BiBitOr, BiBitXor, BiRem, BiLt, BiGt, Block}; use ast::{BlockCheckMode, CaptureByRef, CaptureByValue, CaptureClause}; -use ast::{Crate, CrateConfig, Decl, DeclItem}; -use ast::{DeclLocal, DefaultBlock, DefaultReturn}; +use ast::{ConstImplItem, ConstTraitItem, Crate, CrateConfig}; +use ast::{Decl, DeclItem, DeclLocal, DefaultBlock, DefaultReturn}; use ast::{UnDeref, BiDiv, EMPTY_CTXT, EnumDef, ExplicitSelf}; use ast::{Expr, Expr_, ExprAddrOf, ExprMatch, ExprAgain}; use ast::{ExprAssign, ExprAssignOp, ExprBinary, ExprBlock, ExprBox}; @@ -40,8 +40,9 @@ use ast::{MacStmtWithBraces, MacStmtWithSemicolon, MacStmtWithoutBraces}; use ast::{MutImmutable, MutMutable, Mac_, MacInvocTT, MatchSource}; use ast::{MutTy, BiMul, Mutability}; use ast::{MethodImplItem, NamedField, UnNeg, NoReturn, UnNot}; -use ast::{Pat, PatBox, PatEnum, PatIdent, PatLit, PatMac, PatRange, PatRegion}; -use ast::{PatStruct, PatTup, PatVec, PatWild, PatWildMulti, PatWildSingle}; +use ast::{Pat, PatBox, PatEnum, PatIdent, PatLit, PatQPath, PatMac, PatRange}; +use ast::{PatRegion, PatStruct, PatTup, PatVec, PatWild, PatWildMulti}; +use ast::PatWildSingle; use ast::{PolyTraitRef, QSelf}; use ast::{Return, BiShl, BiShr, Stmt, StmtDecl}; use ast::{StmtExpr, StmtSemi, StmtMac, StructDef, StructField}; @@ -109,6 +110,15 @@ pub enum PathParsingMode { LifetimeAndTypesWithColons, } +/// How to parse a qualified path, whether to allow trailing parameters. +#[derive(Copy, Clone, PartialEq)] +pub enum QPathParsingMode { + /// No trailing parameters, e.g. `<T as Trait>::Item` + NoParameters, + /// Optional parameters, e.g. `<T as Trait>::item::<'a, U>` + MaybeParameters, +} + /// How to parse a bound, whether to allow bound modifiers such as `?`. #[derive(Copy, Clone, PartialEq)] pub enum BoundParsingMode { @@ -1161,6 +1171,20 @@ impl<'a> Parser<'a> { let TyParam {ident, bounds, default, ..} = try!(p.parse_ty_param()); try!(p.expect(&token::Semi)); (ident, TypeTraitItem(bounds, default)) + } else if try!(p.eat_keyword(keywords::Const)) { + let ident = try!(p.parse_ident()); + try!(p.expect(&token::Colon)); + let ty = try!(p.parse_ty_sum()); + let default = if p.check(&token::Eq) { + try!(p.bump()); + let expr = try!(p.parse_expr_nopanic()); + try!(p.commit_expr_expecting(&expr, token::Semi)); + Some(expr) + } else { + try!(p.expect(&token::Semi)); + None + }; + (ident, ConstTraitItem(ty, default)) } else { let style = try!(p.parse_unsafety()); let abi = if try!(p.eat_keyword(keywords::Extern)) { @@ -1334,36 +1358,9 @@ impl<'a> Parser<'a> { try!(self.expect(&token::CloseDelim(token::Paren))); TyTypeof(e) } else if try!(self.eat_lt()) { - // QUALIFIED PATH `<TYPE as TRAIT_REF>::item` - let self_type = try!(self.parse_ty_sum()); - let mut path = if try!(self.eat_keyword(keywords::As) ){ - try!(self.parse_path(LifetimeAndTypesWithoutColons)) - } else { - ast::Path { - span: self.span, - global: false, - segments: vec![] - } - }; - - let qself = QSelf { - ty: self_type, - position: path.segments.len() - }; - - try!(self.expect(&token::Gt)); - try!(self.expect(&token::ModSep)); - - path.segments.push(ast::PathSegment { - identifier: try!(self.parse_ident()), - parameters: ast::PathParameters::none() - }); - - if path.segments.len() == 1 { - path.span.lo = self.last_span.lo; - } - path.span.hi = self.last_span.hi; + let (qself, path) = + try!(self.parse_qualified_path(QPathParsingMode::NoParameters)); TyPath(Some(qself), path) } else if self.check(&token::ModSep) || @@ -1580,6 +1577,61 @@ impl<'a> Parser<'a> { } } + // QUALIFIED PATH `<TYPE [as TRAIT_REF]>::IDENT[::<PARAMS>]` + // Assumes that the leading `<` has been parsed already. + pub fn parse_qualified_path(&mut self, mode: QPathParsingMode) + -> PResult<(QSelf, ast::Path)> { + let self_type = try!(self.parse_ty_sum()); + let mut path = if try!(self.eat_keyword(keywords::As)) { + try!(self.parse_path(LifetimeAndTypesWithoutColons)) + } else { + ast::Path { + span: self.span, + global: false, + segments: vec![] + } + }; + + let qself = QSelf { + ty: self_type, + position: path.segments.len() + }; + + try!(self.expect(&token::Gt)); + try!(self.expect(&token::ModSep)); + + let item_name = try!(self.parse_ident()); + let parameters = match mode { + QPathParsingMode::NoParameters => ast::PathParameters::none(), + QPathParsingMode::MaybeParameters => { + if try!(self.eat(&token::ModSep)) { + try!(self.expect_lt()); + // Consumed `item::<`, go look for types + let (lifetimes, types, bindings) = + try!(self.parse_generic_values_after_lt()); + ast::AngleBracketedParameters(ast::AngleBracketedParameterData { + lifetimes: lifetimes, + types: OwnedSlice::from_vec(types), + bindings: OwnedSlice::from_vec(bindings), + }) + } else { + ast::PathParameters::none() + } + } + }; + path.segments.push(ast::PathSegment { + identifier: item_name, + parameters: parameters + }); + + if path.segments.len() == 1 { + path.span.lo = self.last_span.lo; + } + path.span.hi = self.last_span.hi; + + Ok((qself, path)) + } + /// Parses a path and optional type parameter bounds, depending on the /// mode. The `mode` parameter determines whether lifetimes, types, and/or /// bounds are permitted and whether `::` must precede type parameter @@ -2043,49 +2095,10 @@ impl<'a> Parser<'a> { } _ => { if try!(self.eat_lt()){ - // QUALIFIED PATH `<TYPE as TRAIT_REF>::item::<'a, T>` - let self_type = try!(self.parse_ty_sum()); - let mut path = if try!(self.eat_keyword(keywords::As) ){ - try!(self.parse_path(LifetimeAndTypesWithoutColons)) - } else { - ast::Path { - span: self.span, - global: false, - segments: vec![] - } - }; - let qself = QSelf { - ty: self_type, - position: path.segments.len() - }; - try!(self.expect(&token::Gt)); - try!(self.expect(&token::ModSep)); - - let item_name = try!(self.parse_ident()); - let parameters = if try!(self.eat(&token::ModSep) ){ - try!(self.expect_lt()); - // Consumed `item::<`, go look for types - let (lifetimes, types, bindings) = - try!(self.parse_generic_values_after_lt()); - ast::AngleBracketedParameters(ast::AngleBracketedParameterData { - lifetimes: lifetimes, - types: OwnedSlice::from_vec(types), - bindings: OwnedSlice::from_vec(bindings), - }) - } else { - ast::PathParameters::none() - }; - path.segments.push(ast::PathSegment { - identifier: item_name, - parameters: parameters - }); - if path.segments.len() == 1 { - path.span.lo = self.last_span.lo; - } - path.span.hi = self.last_span.hi; + let (qself, path) = + try!(self.parse_qualified_path(QPathParsingMode::MaybeParameters)); - let hi = self.span.hi; return Ok(self.mk_expr(lo, hi, ExprPath(Some(qself), path))); } if try!(self.eat_keyword(keywords::Move) ){ @@ -3158,16 +3171,25 @@ impl<'a> Parser<'a> { fn parse_pat_range_end(&mut self) -> PResult<P<Expr>> { if self.is_path_start() { let lo = self.span.lo; - let path = try!(self.parse_path(LifetimeAndTypesWithColons)); + let (qself, path) = if try!(self.eat_lt()) { + // Parse a qualified path + let (qself, path) = + try!(self.parse_qualified_path(QPathParsingMode::NoParameters)); + (Some(qself), path) + } else { + // Parse an unqualified path + (None, try!(self.parse_path(LifetimeAndTypesWithColons))) + }; let hi = self.last_span.hi; - Ok(self.mk_expr(lo, hi, ExprPath(None, path))) + Ok(self.mk_expr(lo, hi, ExprPath(qself, path))) } else { self.parse_literal_maybe_minus() } } fn is_path_start(&self) -> bool { - (self.token == token::ModSep || self.token.is_ident() || self.token.is_path()) + (self.token == token::Lt || self.token == token::ModSep + || self.token.is_ident() || self.token.is_path()) && !self.token.is_keyword(keywords::True) && !self.token.is_keyword(keywords::False) } @@ -3243,25 +3265,44 @@ impl<'a> Parser<'a> { pat = try!(self.parse_pat_ident(BindByValue(MutImmutable))); } } else { - // Parse as a general path - let path = try!(self.parse_path(LifetimeAndTypesWithColons)); + let (qself, path) = if try!(self.eat_lt()) { + // Parse a qualified path + let (qself, path) = + try!(self.parse_qualified_path(QPathParsingMode::NoParameters)); + (Some(qself), path) + } else { + // Parse an unqualified path + (None, try!(self.parse_path(LifetimeAndTypesWithColons))) + }; match self.token { token::DotDotDot => { // Parse range let hi = self.last_span.hi; - let begin = self.mk_expr(lo, hi, ExprPath(None, path)); + let begin = self.mk_expr(lo, hi, ExprPath(qself, path)); try!(self.bump()); let end = try!(self.parse_pat_range_end()); pat = PatRange(begin, end); } token::OpenDelim(token::Brace) => { - // Parse struct pattern + if qself.is_some() { + let span = self.span; + self.span_err(span, + "unexpected `{` after qualified path"); + self.abort_if_errors(); + } + // Parse struct pattern try!(self.bump()); let (fields, etc) = try!(self.parse_pat_fields()); try!(self.bump()); pat = PatStruct(path, fields, etc); } token::OpenDelim(token::Paren) => { + if qself.is_some() { + let span = self.span; + self.span_err(span, + "unexpected `(` after qualified path"); + self.abort_if_errors(); + } // Parse tuple struct or enum pattern if self.look_ahead(1, |t| *t == token::DotDot) { // This is a "top constructor only" pat @@ -3278,6 +3319,10 @@ impl<'a> Parser<'a> { pat = PatEnum(path, Some(args)); } } + _ if qself.is_some() => { + // Parse qualified path + pat = PatQPath(qself.unwrap(), path); + } _ => { // Parse nullary enum pat = PatEnum(path, Some(vec![])); @@ -4349,6 +4394,14 @@ impl<'a> Parser<'a> { let typ = try!(self.parse_ty_sum()); try!(self.expect(&token::Semi)); (name, TypeImplItem(typ)) + } else if try!(self.eat_keyword(keywords::Const)) { + let name = try!(self.parse_ident()); + try!(self.expect(&token::Colon)); + let typ = try!(self.parse_ty_sum()); + try!(self.expect(&token::Eq)); + let expr = try!(self.parse_expr_nopanic()); + try!(self.commit_expr_expecting(&expr, token::Semi)); + (name, ConstImplItem(typ, expr)) } else { let (name, inner_attrs, node) = try!(self.parse_impl_method(vis)); attrs.extend(inner_attrs.into_iter()); |